Recently, a quantum dot type light emitting diode has got more and more attention in the field of liquid crystal display. By adopting the quantum dot type light emitting diode as a backlight source, the color purity of a liquid crystal panel can be improved, and meanwhile the color density of a color filter does not need to be strengthened, so that the power consumption of the liquid crystal panel will not be increased. Additionally, the color gamut of the liquid crystal panel will expand accordingly, for example, can be increased by about 30%. Furthermore, by changing the size of a quantum dot, the emission wavelength of the quantum dot type light emitting diode can also be controlled.
FIG. 5 shows a sectional view of a liquid crystal display using a quantum dot type light emitting diode as a backlight according to prior art. As shown in FIG. 5, the liquid crystal display 80 mainly includes a backboard 81, and a light guide plate 82 and a backlight 83, which are both arranged in the backboard 81. A quantum dot unit 84 is arranged between the light guide plate 82 and the backlight 83. Light from the backlight 83 enters the light guide plate 82 after passing through the quantum dot unit 84. The quantum dot unit 84 is positioned by a heat sink 85 fixed on the backboard 81. The liquid crystal display 80 further includes a front frame 86 and a middle frame 87, which mutually cooperate for clamping a liquid crystal panel 89, wherein the middle frame 87 is provided with a transverse part 87a used for positioning the rear surface of the liquid crystal panel 89, and a lateral part 87b, which is vertical to the transverse part 87a and is extended from the inner side of the front frame 86 to the bottom wall of the backboard 81 along a front-to-back direction. The lateral part 87b can be cooperatively assembled with the backboard 81 through such connecting elements as a hook (not shown) or the like, in order to position the middle frame 87.
At present, for the liquid crystal display, an ultra-narrow frame is a fashionable pursuit. As a means of achieving the ultra-narrow frame, the frame of the backlight module is also required to be as narrow as possible in design. In order to achieve the narrow frame, the front frame can be narrowed. However, this can only narrow the frame of the liquid crystal display to a small extent, and is possible to result in weakening the mechanical strength of the entire backlight module. In addition, the narrow frame can also be achieved by decreasing the thickness of the side wall of the heat sink, but this will affect the heat dissipation effect of the liquid crystal display.
Thus, a technical solution is needed, which can greatly narrow the frame without resulting in other problems of the liquid crystal display.